WDPN31 PGTW 281500
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 20W (NESAT) WARNING NR 21//
RMKS/
1. FOR METEOROLOGISTS.
2. 12 HOUR SUMMARY AND ANALYSIS.
   A. TYPHOON (TY) 20W (NESAT), LOCATED APPROXIMATELY 525 NM EAST-
SOUTHEAST OF HANOI, VIETNAM, HAS TRACKED WEST-NORTHWESTWARD AT 12 
KNOTS OVER THE PAST SIX HOURS. ANIMATED INFRARED (IR) SATELLITE 
IMAGERY SHOWS A LARGE, RAGGED EYE FROM WHICH THE INITIAL POSITION 
WAS BASED WITH FAIR CONFIDENCE. A 281211Z SSMIS MICROWAVE IMAGE 
DEPICTS DEEP CONVECTIVE BANDING LOOSELY WRAPPING ALMOST COMPLETELY 
AROUND THE LLCC. THE INITIAL INTENSITY IS BASED ON A RJTD DVORAK 
ESTIMATE OF 65 KNOTS. WATER VAPOR IMAGERY INDICATES EXCELLENT 
EQUATORWARD OUTFLOW AND IMPROVING POLEWARD OUTFLOW. TY 20W IS 
CURRENTLY TRACKING ALONG THE SOUTHERN PERIPHERY OF A DEEP LAYER 
SUBTROPICAL STEERING RIDGE. 
3. FORECAST REASONING.
   A. NO CHANGE TO FORECAST PHILOSOPHY.
   B. TY 20W IS EXPECTED TO CONTINUE TRACKING UNDER THE STEERING 
INFLUENCE OF THE SUBTROPICAL STEERING RIDGE TO THE NORTH THROUGHOUT 
THE FORECAST PERIOD. TY 20W SHOULD SLIGHTLY INTENSIFY BEFORE 
WEAKENING AS IT MAKES LANDFALL OVER HAINAN. AFTER TAU 48, THE SYSTEM 
WILL MAKE LANDFALL OVER NORTHERN VIETNAM.
   C. THE SYSTEM WILL DISSIPATE OVER LAND BY TAU 96. THE NUMERICAL 
MODEL GUIDANCE IS IN GOOD AGREEMENT. THEREFORE, THIS FORECAST IS IN 
GOOD AGREEMENT WITH MODEL CONSENSUS.//
NNNN